Chapter 8- Cell Division And Reproduction Flashcards
Cell division is also known as cell _____.
Reproduction
The two “daughter” cells that result from cell division are genetically identical to _____ and _____.
Each other
Their original “parent cell”
What are chromosomes? (Basic)
The structures that contain most of a cell’s genetic information
During cell division, daughter cells receive _____ set of ______ chromosomes from the _____ parent cell.
One
Identical
Lone, original
Each offspring cell from cell division is genetically _____ to _____ and _____.
Identical
The other (each other daughter cell)
Original parent cell
What is asexual reproduction?
The creation of genetically identical offspring by a single parent, without participation of sperm and egg.
Asexual reproduction results in a _____.
Clone
Many ______-celled organisms can reproduce asexually.
Multi
In asexual reproduction, what is the one simple principle of inheritance?
The lone parent and each of its offspring have identical genes
Sexual reproductions requires: _____.
The fusion of gametes, eggs, and sperm.
The production of gametes involves a particular type of ______ occurring only in _____ organs.
Cell division
Reproductive organs
Where are gametes formed in men and women?
Testes and ovaries
A gamete has _____ chromosomes as the parent cell that gave rise to it.
Half as many
Gametes contain _____ combinations of genes.
Unique
In sexual reproduction, offspring are ______ to _____ and ______.
Not identical
Each other (exception: identical twins)
Their parents
Offspring resulting from sexual reproduction generally resemble ______ more than they resemble _____ of the same _____.
Their parents
Unrelated individuals
Species
Offspring of sexual reproduction are _____ upon a common theme of family _____.
Variations
Resemblance
Sexual reproduction requires two _____ with their own _____.
Parents
Gametes
The trillions of _____ in a _____ reproducing organism develop from a _____ fertilized _____ cell.
Cells
Sexually
Single
Fertilized
A zygote is what?
Fertilized egg
Once an organism is fully grown, cell division aids in _____, _____, and _____ of cells that die.
Renewal
Repair
Replacement
Every second, how many cells must divide to replace dead or lost cells?
Millions
Many single celled organisms such as _____ or the ______ yeast cell reproduce by _____.
Prokaryotes
Eukaryotic
Cellular division
Prokaryotes (single celled _____ and _____) reproduce by _____.
Bacteria
Archae
Binary fission
Binary fusion is a type of _____.
Cell division
Binary fission means “_____”.
Dividing in half
Fission is _____, fusion is _____.
Dividing
Combining
In typical prokaryotes, most genes are carried on _____ that, with associated proteins, constitutes an organism’s _____.
One circular DNA molecule
Single chromosome
What are the 3 steps of binary fission?
- As the chromosome duplicates, one copy moves toward the opposite end of the cell
- Cell elongates, chromosomes keep moving
- Once chromosome duplication is complete and cell is 2x size, plasma membrane pinches inward and more cell wall is made, dividing the parent cell into two daughter cells.
Binary fission is accomplished by _____, elongating and ______ and finally _____ dividing the parent cell into _____.
Chromosome duplication
Separation of duplicated chromosome
Pinching of the plasma membrane
2 identical daughter cells
Why is binary fission classified as asexual reproduction?
Because the genetically identical offspring inherit their DNA from a single parent
In binary fission, what occurs first? Building the cell wall, or pinching the plasma membrane?
Pinching of the plasma membrane as the cell wall is being formed
Eukaryotic cell’s are more _____ and much _____ than _____ cells.
Complex
Larger
Prokaryotic
Genes are the units of _____ that specify an organism’s ______.
Information
Inherited traits
Almost all the genes in the cells of humans and other eukaryotes are found in the _____, grouped into _____ of chromosomes.
Multiples
How many chromosomes do normal humans have?
46
Human cells carry how many genes? How about a typical bacterium?
Just under 21,000
About 3,000
What is chromatin?
The long DNA molecule consisting of hundreds to thousands of genes and prtein molecules
Chromatin consists of roughly equal amounts of _____ and _____.
DNA
Protein
Chromatin will coil into ______ as a cell prepares to _____.
Chromosomes
Divide
Before chromosomes condense and the cell divides, the chromosomes of eukaryotic cells are _____.
Duplicated
The chromosome duplicates, and the resulting two chromosomes are called _____ and attached at the _____.
Sister Chromatids
Centromere
What is the centromere?
The point of attachment (proteins) of sister chromatids
Joined copies of the original chromosome are called _____.
Sister chromatids
The two sister chromatids are attached along there entire length by proteins (T/F)?
True
Where are sister chromatids most closely attached?
Attached by proteins, most closely at the centromere
The centromere is visible as the “_____”.
A narrow waist
What happens to the sister chromatids when a cell divides?
The sisters chromatids of a duplicated chromosome separate from each other
Once separated, each sister chromatid becomes ______.
An individual chromosome identical to the cell’s original
What occurs to the newly formed identical chromosomes when the cell divides?
Each new chromosome goes into their own daughter cell
Each daughter cell receives a complete and identical set of _____.
Chromosomes
A typical dividing human cell has #_____ duplicated chromosomes, so #_____ chromatids. Each daughter cell has #_____ single chromosomes.
46
92
46
When does a chromosome consist of two identical chromatids?
When cell is preparing to divide and has duplicated its chromosomes but before the chromatids (duplicates) actually separate.
Cell division is the basis of _____ for every organism.
Reproduction
What is the cell cycle?
An ordered sequence of events that run from the instant a cell is first formed from a dividing parent cell until its own division into two cells
What are the 2 stages of the cell cycle?
Interphase
Mitosis phase
Most of the cell cycle is spent during what phase?
Interphase
What is interphase?
The cell approximately doubles everything in its cytoplasm and replicates it’s DNA
What % of the cell cycle consists of Interphase?
90%
During interphase, the cell will become _____ and making more _____.
The supply of _____ increases and cytoplasmic organelles such as _____ and _____.
Larger
Cytoplasm
Digestive proteins (small intestinal cell)
Mitochondria and ribosomes
What are the 3 subphases of Interphase?
- G1 Phase (“first gap”)
- S Phase (“synthesis” of DNA, DNA replication)
- G2 phase (“second gap)
Cells are very active and _____ throughout all 3 subphases of Interphase.
Grow
How long does the S phase last?
Approximately half the time of Interphase
What occurs during S phase of Interphase?
Chromosomes are duplicated
What occurs during G2 phase of Interphase?
Cell completes preparation for cell division
What is the M phase?
The mitotic phase
What is the mitotic phase?
The interval of the cell cycle when the cell physically divides
The M phase accounts for what % of time of the cell cycle?
10%
What are the two overlapping phases of the M Phase?
Mitosis
Cytokinesis
What occurs during the mitosis stage of the M phase?
The nucleus and it’s contents are (most important is the duplicated chromosomes) divide and are distributed to the two daughter cell’s nuclei
When does cytokinesis of the M phase begin?
Before mitosis ends
What occurs during cytokinesis?
The cytoplasm is split into two
The combination of mitosis and cytokinesis results in what?
2 daughter cells with their own:
Nucleus
Surrounding cytoplasm
Organelles
Plasma membrane
Mitosis is unique to ____.
Eukaryotes
Error in chromosome distribution (in yeast cells) occurs only once in every _____ cell divisions.
100,000
How many stages comprise the mitosis stage of the M phase?
5
What are the 5 stages of mitosis?
Prophase Prometaphase Metaphase Anaphase Telophase
What is the mitotic spindle?
A football shaped structure of microtubule fibers and associated proteins that guides the separation of the two sets of daughter chromosomes
Where do spindle microtubules (of the mitotic spindle) come from?
The centrosomes, microtubule organizing regions in the cytoplasm of eukaryotic cells
What occurs during prophase? In the nucleus and the cytoplasm
In the nucleus: chromatin fibers become more tightly coiled and folded forming discrete chromosomes
In the cytoplasm, the mitotic spindle begins to form as microtubules rapidly grow from the centrosomes, which begin moving away from each other
Cytokinesis is different in plants and animals. T/F
True
Cytokinesis overlaps with ____.
Telophase
Cytokinesis occurs via ____ in animal cells.
Cleavage
What is the first sign of cleavage in animal cells?
Cleavage furrow
What is the cleavage furrow?
A shallow grove in the cell’s surface
At the cleavage furrow, what exists?
A ring of microfilaments (actin and myosin)
What happens, at the cleavage furrow, as actin and myosin interact?
The ring of microfilaments contracts, eventually pinching shut
As the cleavage furrow deepens, what occurs?
Pinches the parent cell into two
In plants, what property prevents contraction of the cell?
Stiff cell walls
During telophase, membranous vesicles collect at the ____ of the _____ cell.
Middle
Parent
In plants during cytokinesis, what occurs to the vesicles collected in the middle?
The vesicles fuse, forming a membranous disc called the cell plate
What is the cell plate?
A membranous disc created by the fusion of membranous vesicles within plant cells
The cell plate will continue to grow outwards as what occurs?
More membranous vesicles fuse with it
The membrane of the cell plate eventually fuses with the _____ and the cell plates contents join the parental cell wall.
Plasma membrane
